P947: TREATMENT PATTERNS AND OUTCOMES OF RE-INDUCTION THERAPIES PRIOR TO STEM CELL TRANSPLANTATION IN PATIENTS WITH RELAPSED/REFRACTORY MULTIPLE MYELOMA TREATED IN CLINICAL PRACTICE IN GERMANY
Authors: Sandra Sauer, Monika Engelhardt, Karolin Trautmann-Grill, Christoph Kimmich, Mathias Hänel, Martin Schmidt-Hieber, Hans Salwender, Carmen Flossmann, Hiltrud Heckmann, Franziska Ertel, Andrea Friederich, Sachin Patel, Sabine Piesch, Barbara Thun, Marc S. Raab
Journal: HemaSphere (2023)

Topic: 14. Myeloma and other monoclonal gammopathies - Clinical Background: The efficacy of salvage stem cell transplantation (SCT) after re-induction with modern triplet or quadruplet regimens has been shown in clinical studies. However, there are limited data concerning the optimal choice of re-induction therapy for patients (pts) with relapsed/refractory multiple myeloma (RRMM) prior to salvage SCT in clinical practice. Aims: To describe characteristics, treatment patterns and outcomes of pts with RRMM in Germany, who received re-induction therapies prior to a planned SCT. Methods: A national retrospective chart review was conducted at 7 hospitals with active transplant centers in 2021-2022 and included pts treated with re induction regimens in second or third line (2L/3L, defined as index therapy line) between Jan 2016 and Dec 2019. The following data were extracted from medical records until 30 Sep 2020, death, or lost to follow-up, whichever occurred first: pt demographics, disease characteristics, treatment sequences, response to treatment, disease progression and survival. Results: Of the 171 medical records analyzed, 134 pts received a re-induction in 2L and 37 in 3L. Pt characteristics are described in Table 1. Over half (59%) of pts were male, median age was 61 years. At start of re-induction therapy, median ECOG PS was 0. In first line (1L) of therapy, all pts received anti-MM therapies, mostly bortezomib (V)-based regimens (91%, n=155). Most (88%, n=150) pts had received SCT in 1L, as single (79%) or tandem (21%) autologous SCT (ASCT). The median 1L duration was 6 (1–168) months. For 31% (n=53) of the pts who received maintenance therapy in 1L, their total median 1L duration was 33 (10-168) months. For re-induction in 2L/3L, carfilzomib (K)-based regimens were widely (49%, n=83) used, followed by daratumumab (D)-based (21%, n=36), V-based (17%, n=29), and other (14%, n=23) regimens. Median duration of index therapy line was 9 (1–44) months. All pts underwent SCT in 2L/3L: 85% single ASCT, 10% allogeneic SCT, 4% ASCT plus allogeneic SCT, and 1% tandem ASCT. After SCT, in 54% (n=92) of pts therapy was continued (62% in 2L; 24% in 3L) mainly with lenalidomide (86%) to maintain disease response. Overall response rates (ORRs) were high after re-induction (87%) and SCT (96%) in 2L/3L. Complete response (CR) or better was achieved by 6% and 16% of pts after re-induction or SCT, respectively. ORRs were similar for 2L and 3L pts, a higher proportion of pts achieved CR or better in 3L vs 2L. From index date, median time to next treatment line was 31 months (95% CI: 29; 37); median progression free survival (mPFS) was 29 months (95% CI: 26; 32) and median overall survival was not reached after 4.2 years of follow-up. When comparing pts receiving K-based regimens (n=83) with those receiving non-K-based regimens (n=88) for re-induction in 2L/3L, median duration of index therapy line was 8 (1-44) months and 9 (1-43) months, respectively. After SCT in 2L/3L, more than half (52% in K-based and 56% in non-K-based subgroup) of pts continued therapy, mostly with lenalidomide (88% and 84%, respectively). Similar ORRs were found for K-based and non-K-based subgroups after re-induction (84% and 86%) and after SCT (99% and 93%), respectively. In both subgroups, mPFS was 29 months ([95% CI: 24; 31] and [95% CI: 26; 36], respectively).Summary/Conclusion: In this selected pt population with RRMM treated in clinical practice in Germany, the benefits of re-induction therapy with salvage SCT are shown. Re-induction therapy in 2L/3L led to deep responses, long PFS, and prolonged time to next treatment. Keywords: Induction, Multiple myeloma, Regimen, Stem cell transplant